1. Field of the Invention
The invention relates to a technique, specifically apparatus and accompanying methods, for use in a client-server environment for booting an operating system (O/S) on a client computer through a networked connection to a server. This technique is particularly, though not exclusively, suited for use in booting 32-bit personal computer (PC) operating systems and can be advantageously used to simplify system administration and significantly reduce administrative costs in, e.g., large enterprise environments.
2. Description of the Prior Art
Over the past decade, personal computer (PC) usage has increased substantially to the point where currently PCs (including workstations) have diffused into many aspects of a business organization. Coincident with this phenomena, a desire has increasingly arisen among computer users in a common organization to readily share computer files. This desire, particularly when fueled by historically decreasing costs of network equipment, has led to an expanding number of network installations throughout the business community to facilitate file sharing and electronic communication not only among users in a common organization, but also with users at other organizations and locations. Moreover, as these costs of increasingly sophisticated PCs and network equipment continue to fall, networked computer usage is penetrating increasingly smaller organizations as the expected benefits to those organizations, such as expanded productivity, outweigh the costs associated therewith.
If current cost and technology trends continue, PC usage should ideally proliferate throughout businesses to a point of becoming rather ubiquitous and inter-connected, i.e., at least ideally and at some time in the future where most people will possess their own PC and where such PCs will become increasingly inter-networked with each other.
However, in reality, a significant impediment to networking has been and continues to be cost--not just the initial and replacement cost of hardware, i.e. each computer and associated network equipment, and the time and effort required to successfully connect them together, but also the cost of administering, on a post-installation basis, each and every networked computer. This latter cost, which often vastly exceeds the cost of the former, includes the cost of servicing, including updating, the software stored on each and every networked computer. In a typical enterprise environment having thousands or tens of thousands of networked client PCs--which is very common today, it is very expensive for a network administrator, or more generally speaking in a large enterprise a member of an information technology (IT) department, to physically visit each user and service his(her) client computer as required. Inasmuch as a predominant component of total post-installation administrative costs is for client software, software and computer manufacturers have recently embarked on various product initiatives aimed at reducing the cost of maintaining installed client software. For the most part, these efforts, as they relate to software manufacturers, are expected to involve providing a version of their software products that can be installed and centrally maintained on a network server and then identically downloaded as a single image, via the network, to each and every client PC on which that software is to be installed. This concept, as currently envisioned, could be extended past just a single application to encompass all or a set of applications that would be common to most, if not all, of the PCs on a network. By doing so, the intent would be to eliminate a need to separately administer the software stored on every single workstation on the network in favor of doing so just once--on a shared installation image on a server. Moreover, as part of these initiatives, automated techniques are being developed to permit such administration to occur remotely through the network thereby eliminating any need for an individual to physically visit each such PC and personally service its software.
To achieve effective centralized administration of network clients, ideally a server should store a complete image of the software, including the operating system (O/S), utilized by a client computer. As each client computer is powered-on by its user, that client would establish a connection with the server and boot its operating system from the server. In particular, an operating system image would be stored on the server and would be transferred, via the network, to the client onto which that operating system would be set-up and run. Application software could then be transferred from the server, as needed, to the client and then run on the client. Proceeding in this fashion could eliminate the need for any hard disk storage on each client, thereby facilitating use of low-cost "diskless" computers. Alternatively, application software could remain on the server and be executed therefrom.
Unfortunately, serious impediments exist that, in practice, effectively limit the extent to which a client computer can be centrally administered and, specifically, a client O/S booted from a network server.
Currently, a common and widely used 32-bit PC operating system, specifically Windows 95 O/S available from Microsoft Corporation of Redmond, Washington (which also owns the registered trademark "Windows 95"), provides rather limited and problematic server-based set-up abilities. Ideally, for server-based set-up of a client PC, the client O/S should be bootable from either a system floppy diskette or a ROM, situated within the PC, and then download all the other system files from a network file server. The ROM would store suitable code that emulates the floppy disk.
At present, in practice, during the course of configuring a particular client computer for server-based setup of the Windows 95 O/S, this O/S would create two directories on the client computer for subsequent transfer to a server: a machine directory which stores configuration information for that specific client, and a share directory which contains shared O/S files. During the boot process, both directories are used to control the remainder of the set-up process and load appropriate O/S files onto the client. It was empirically found that, from time to time--though not all the time, while creating the directories on the server, the client computer would simply halt, i.e. "freeze". In other instances where the directories were successfully created, users found that sometimes during the network boot process, the client computer would also halt--again from time to time, though here too not always. Moreover, apart from these problems, the Windows 95 operating system, as it currently stands, apparently does not support network booting through a 32-bit local area network (LAN) adapter. While 16-bit ISA (Industry Standard Architecture) network (e.g., LAN) adapters were prevalent at the time the Windows 95 O/S was introduced, currently 32-bit adapters, particularly PCI (Peripheral Component Interconnect) type adapters predominate a network adapter market. Lastly, difficulties arose in changing a server-based installation of a Windows 95 client, thereby frustrating centralized remote administration of the application software to be downloaded to that client.
Given these difficulties, the art has apparently veered away from the concept of providing server-based setup of a 32-bit PC O/S in favor of using different approaches for centralized client administration. One such approach relies on using an inexpensive client PC, i.e., a so-called "thin client", to essentially transmit user keystrokes to a server at which they are processed and at which applications are run. The results would then be returned, via the network to the client PC, and displayed to the user through an appropriate graphical user interface executing at the client PC. While this approach eliminates a need to store and execute application software on a client PC, it does so at the expense of shifting application processing to a network server. In a large networked environment, the added processing load placed on the server could render this approach impractical. While the use of inexpensive PCs, such as "thin clients" and "diskless" PCs certainly have merit to reduce costs and centralize administration in large networked enterprise environments, such PCs, as presently envisioned, still require an operating system, which, for effective centralized administration, should be booted from a network.
Therefore, a need exists in the art for a technique, specifically apparatus and accompanying methods, for use in a client-server environment for reliably booting an operating system, such as a 32-bit O/S, on a client PC from a network server. Moreover, such a technique, should be fully operative with all currently available LAN adapters, whether, e.g., 16- or 32-bit and permit changes to be easily made to any server-based installation of client software. Through use of such a technique, the processing load on the network server(s) can be advantageously reduced by utilizing local client RAM memory and CPU resources, rather than server resources, for client application and client O/S processing. Consequently, by utilizing these client resources, server complexity and cost, such as those occasioned by large amounts of RAM and multiple CPUs that might otherwise be required, could be sharply reduced. By virtue of meeting these needs and being capable of network booting an O/S, such as the Windows 95 O/S, on substantially any client PC, including thin-clients and diskless PCs, such a technique should find widespread use in implementing effective centralized client administration in, e.g., large networked enterprises and in providing significant administrative cost savings.